Oscillating device activated by bimetallic element



Sept 28, 1954 B. s. NICHOLS 25690950 OSCILLATING DEVICE ACTIVATED BY BIMETALLIC ELEMENT Filed Sept. 21, 1953 h 36 Bi-Metoi IN ENTOR 5m? 5 Mex/01.5

i E ATTORNE? Patented Sept. 28, 1954 OS-CILLATING DEVICE ACTIVATED BY BIMETALLIC ELEMENT Brett S. Nichols, Mineola, N. Y., assignor to Demanco Products Inc., Westbury, Long Island, N. Y., a corporation of New York Application September 21, 1953, Serial No. 381,271

13 Claims.

My present invention relates generally to motors, and has particular reference to a motive unit which generates oscillatory movements as the result of distortion of a bi-metallic element whose opposite surfaces are subjected to different temperatures at successive intervals of time. Coordinately, my invention relates to oscillating devices in which the driving motor is of the character mentioned.

A general object of the invention is to improve the efficiency, reliability, and versatility of the motive units described and illustrated in the pending patent application of Brett S. Nichols, Serial No. 321,109. The motor therein disclosed affords a simplified and unusually inexpensive source of relatively minute motive power suitable for such uses as the animation of light-weight advertising displays, amusement devices, and similar items. The motor derives its energy from an activator having a temperature appreciably different from the ambient temperature, the temperature differential being utilized by means of the distortions of the bi-metallic element. This element is of the well-known type whose opposite surfaces have different temperature coefficients of expansion.

More particularly, motors of this type involve a resilient deflectable strip secured in association with the activator in such a way that one end of the strip is anchored at a point of pivotal support while the strip extends in an adjacent relation to the activator. The strip includes or is formed of a bi-metallic element adapted to distort upon subjection to the two different temperatures which are thus afforded. The distortion is effective to initiate a swinging movement of the strip away from the activator, and it is during this swing that the bi-metallic element is afforded an opportunity to resume its normal shape, so that upon the completion of the return swing the activator is again effective to distort the bi-metallic element and thereby repeat the operation.

In the preferred embodiment of the present invention, the source of temperature difierential is an ordinary electric lamp of relatively low wattage. The heat generated by such a lamp is quite small, but is nevertheless sufficient for the present purpose. Where the motor is to be used for the animation of advertising displays such as the cardboard devices commonly employed on store counters and in store windows, the use of an electric lamp as the source of temperature differential is particularly advantageous because it can be utilized at the same time to illuminate the display.

It has been found that the heat radiated by such a lamp often warms up the surrounding region to an excessive degree and varies the ambient temperature gradient to such an extent that the desired cooling-off of the bi-metallic element during the outward swing does not occur as quickly and reliably as it should, the smooth and efficient operation of the motor being correspondingly impaired. In addition, the heat transfer characteristics of each particular installation have been found to difier and sometimes seriously affect the motor operation. For example, the size and shape of the enclosure within which the motor operates, as well as the amount and kind of ventilation afforded the enclosure, serve to vary the operating characteristics of the motor. It is a principal object of the present invention to overcome these difficulties and to provide novel means for obtaining optimum performance from a motor of this type under a wide variety of operating conditions.

Another object of the invention resides in the provision of simple adjustable means to selectively vary the amplitude and other characteristics of oscillation of the swingingstrip as well as the duration of time spent near or at its heat pick-up position on the return swing. More particularly, the motor of the present invention is provided with a tiltable mount for placing the extreme return position of the swinging strip at a selected distance from the dead-center axis of the swing. The tiltable mounting also serves to compensate for irregularities in the motor supporting surface.

Still another object resides in the provision of a shield for engagement over the lamp to serve as a barrier to the transmission of radiant heat from the lamp to the space in which the movements of the bi-metallic element take place, and which is movably mounted to vary the shielding effect and to permit removal and replacement of the lamp.

The preferred way of achieving the objectives and advantages of the invention is illustrated in the accompanying drawing, in which:

Figure l is an elevational View of the working parts of an illustrative oscillating device constructed in accordance with the present invention, showing a position of outward swinging oscillation in dot-and-dash outline;

Figure 2 is a view taken at right angles to Figure 1, showing the shield in a second position in dot-and-dash outline;

Figure 3 is a fragmentary elevational view, greatly enlarged, showing an amplitude-varying means of the invention;

Figure 4 i a fragmentary elevational view, greatly enlarged, showing the adjustable tiltable mounting means; and

Figure 5 is a fragmentary view similar to Figure 1, illustrating a modified construction.

In the device shown in Figures 1-4, represents an ordinary electric lamp of the kind which has a globular filament enclosure, the lamp having a relatively low wattage such as 60 watts or so, and mounted in an ordinary lamp socket 2! The socket is secured, in any suitable fashion, to a supporting bracket 22 by means of which the lamp is mounted in appropriate association with a display or other oscillating device in connection with which it is to be used;

The bracket 22 includes a. generally horizontal member or bar 23, upon which the socket 2| is firmly supported, and a substantially rigid upstanding member 24 which extends alongside of and is slightly spaced from the socket-.2 I.

Arranged in underlying relation to the rigid bar 23 is a resilient bar 25 which has one end portion 26 fixed to the bar 23, as by a rivet 27. The other end 23 of the resilient bar 25 is fixedly secured to a relatively rigid base plate or bar 29.. The part 29 is secured in any convenient or appropriate way to the table or fioor upon which the device is to function, or may be secured directly to a fixed part of the display itself.

A thumb screw or equivalent threaded element 36 extends transversely through the bar 23, in threaded engagement with the latter, and abuts against the end portion 28 of the resilient bar 25. Upon rotation of the thumb screw 32), the bar 23, and hence the bracket as a whole, is caused to move angularly relative to the base bar 28, as indicated by the dot-and-dash lines in Figure 4. As the base bar 29 is positionally fixed, the resili-r ent bar 24 serves to mount the bracket 22 for tilting movement with respect to the fixed sup: port, and the thumb screw 3&3 serves to retain the bracket in any selected tilted position.

Secured to the upstanding arm 24 of the bracket 22, by rivets 33 or the like, is a resilient deflectable strip which extends upwards in adjacent relation to the lamp 2B. As indicated and suggested in the aforementioned pending patent application, this strip may be constructed in various ways. It includes as a part thereof a bi-metallic element so shaped and positioned that the heat of the lamp is efiective to distort it and by such distortion to initiate a swinging movement of the strip away from the lamp. I have chosen to show the strip formed of a lower springy metallic element M, an intermediate bi-metallic strip 35 of wellknown distortable character, and an upper segment 36. These parts are secured together in any convenient manner and the element 35 is so shaped and positioned that it normally lies in close proximity to the lamp 29. The two metals of which the element 35 is formed are so arranged with respect to the lamp that the heat from the lamp will distort the element to initiate a swinging movement of the entire deflectable strip away from the lamp.

For illustrative purposes I have shown an element 3'5, intended to represent part of an advertising display device, secured to the free end of the segment 35. The element 31 may be composed of cardboard or the like, and may have an appropriate cardboard loop 3 8 formed on it by means of which it is frictionally supported upon the free end of the segment 36. The element 31 constitutes a load which is so designed, in relation to the shape and disposition of the defiectable strip on which it is mounted, that an oscillation of substantial magnitude may be achieved. In the illustrated construction, the parts are intended to swing back and forth approximately between the full-line and the dot-and-dash outline positions, as shown in Figure 1. More specifically, the center of gravity of the load is so located (and adjusted by appropriate weights if needed) that when the bi-metallic element 35 is distorted under the influence of the lamp 28, the center of gravity moves past the dead center axis extending vertically through the point of pivotal support.

Interposed between the lamp 129 and the bimetallic element 35 is a metal shield 49 which is heat-conductive yet opaque to the radiant energy emanating from the lamp. Where the lamp is of the, ordinary shape shown, provided with a substantially globular glass filament enclosure, the shield can be conveniently formed of a metal strip bent into the general shape of a questionmark. This permits the shield to conformably engage over the top and side of the lamp. The lower end portion 4! of the shield Ail is pivoted to the bracket bar 24 (by one of the rivets 33 if desired) and spaced from the bar 24 by an insulating disc 42 so that the shield may be swung to the dotand-dash line position of Figure 2, to permit the insertion and removal of the lamp 25 from socket 2i, and for other purposes appearing more fully hereinafter.

Arranged along the outer surface of bar 2% is a resilient member 44 having its lower end portion 43 secured to the bar by the rivets 33. The resilient member A4 extends upwardly along and spaced from the element M on the outside of the latter. A thumb screw or other threaded element 45 extends transversely through and in threaded engagement with the upper end portion at of the resilient member 44. The inner end of the thumbscrew 45 is positioned to be encountered by the strip 34 on the outward swing of the strip. The member 44 will thus serve as a resilient abutment for the strip at the end of its outward swing, and the amplitude of oscillation of the strip may be selectively controlled by rotating the thumb screw and thus adjusting its position.

In operation, the lamp is turned on and the bulb becomes heated in well-known fashion. This heat is transferred to the metal shield ill, and through it to the element 35, causing a distortion of the latter. The parts are so designed that the distortion is effective to move the center of gravity of the swinging assembly past the dead center axis, and as this happens the weight of the load amplifies the swinging movement, that has been initiated. Depending upon the size, shape, resilience and other characteristics of the deflectable strip and of the load itself, swinging movements will tend to reach an extreme position at which the stress upon the resilient strip is sufiioient to impart a returning impulse. I In the present device the point of return can be positionally controlled by the abutment 45. As the parts tend to resume their initial positions, the center of gravity returns across the dead center axis and becomes efiective to complete the return swing. In the meantime, the bi-metallic element 35 has had an opportunity to return, at least partly, to its initial undistorted shape, and the process is repeated as the element 35 comes again into con tact with the heated shield 4i In many installations, the thermal characteristics of the particular location, as well as the loading effected by the particular display elemain bi-metallic element 35'.

be too great to permit sufficient distortion of the strip to carry the center of gravity past the dead center axis, or the natural period of oscillation may be such that the bimetallic element 35 spends so great a portion of the period in contact with the shield 40 that it becomes overheated and is not sufficiently cooled during the remainder of the period. Conditions like these,

- and other similar impediments to smooth operation, can be compensated for by rotation of the thumb screw 30 in one direction or the other, as may be required, to effect tilting movement of the bracket 22. This will vary the extreme return swing position, shown in full lines in Figure 1, moving it closer toor further away from the dead center axis.

The tiltable mounting may also be used to effect irregular and unusual movements of the strip, such as longer dwell in one or the other end position, or oscillations of faster character in one direction than in the other, etc.

Under certain thermal and loading conditions of operation, it may also be required or desirable to increase or decrease the amplitude of strip oscillation to provide more or less cooling effect, or it may be required to shorten the outward swing of the strip to counteract excessive loading. These and other results may be accomplished by rotation of the thumb screw 45 so as to engage the element 34 at different selected positions of its outward swing.

The shield 40 may also be adapted for various thermal operating conditions by rotative movement between the full line and dot-and-dash line positions shown in Figure 2. While the shield is normally operative in its full line position, it may be desirable under certain conditions to transmit radiant heat from the lamp to the space in which the movements of the bi-metallic element 35 takes place, the amount of transmission of such radiant heat being determined by the angular disposition of the shield 40. This adjustment may be required when the motor is operating in a well ventilated location where the heat from the lamp is rapidly removed and the lamp temperature is relatively low.

In Figure I have illustrated a modified construction in which the lower part of the deflectable strip is formed of a second bi-metallic element 50 whose heat responsive surfaces are deliberately reversed with respect to those of the (In other respects the parts are the same as those previously described except that the adjusting elements 44, 45, 46 have been omitted from the structure; corresponding reference numerals have therefore been applied.) This modified construction is effective to compensate automatically for a condition in which overheating of the ambient region tends to make the return swing of the strip sluggish. In such circumstances the main bi-metallic element 35' is often slow to cool and to return toward undistorted condition, but the very overheating that causes this sluggishness is effective to bend or distort the bi-metallic element 50 in a direction to rectify the condition. For example, as viewed in Figure 5, an overheating of the region to the right of the lamp 20' may result in a persistent straightening out (toward the right) of the element 35', but this is automatically compensated for by a bending of the upper end of the element 50 toward the left.

From the foregoing, it is seen that the present invention provides a motor which is well adaptedfor eflicient, reliable and versatile operation under widely varying thermal and loading conditions, so that the device Will provide optimum performance in almost any location and may be used with a wide variety of display elements or loads.

In general it will be understood that those skilled in the art will be enabled to modify the details herein described and depicted without necessarily departing from the spirit and scope of the invention. It is intended, therefore, that these details be considered as illustrative, not in a limiting sense.

Having thus described my invention what I claim as new and desire to secure by Letters Patent is:

1. An oscillating device of the kind described, comprising an electric lamp, a resilient deflectable strip secured at one end to a point of pivotal support and extending in adjacent relation to said lamp, said strip including as a part thereof a bi-metallic element so shaped and positioned that the heat of the lamp is effective to distort it and by such distortion to initiate a swinging movement of the strip away from the lamp, a load carried by the free end of the strip and having its center of gravity so located that as the strip moves under the influence of said distortion the center of gravity is carried past the dead center axis which extends vertically through said point of support, thereby amplifying the swinging movement away from the lamp, and adjustable means for varying the amplitude of oscillation of said strip, said means comprising a resilient abutment member positioned to be encountered by said strip at the end of its outward swing, and means for adjusting the position of said abutment member.

2. An oscillating device of the kind described, comprising an electric lamp, a resilient deflectable strip secured at one end to a point of pivotal support and extending in adjacent relation to said lamp, said strip including as a part thereof a bi-metallic element so shaped and positioned that the heat of the lamp is effective to distort it and by such distortion to initiate a swinging movement of the strip away from the lamp, a load carried by the free end of the strip and hav-, ing its center of gravity so located that as the strip moves under the influence of said distortion the center of gravity is carried past the dead center axis which extends vertically through said point of support, thereby amplifying the swinging movement away from the lamp, and adjustable means for selectively varying the locations of said strip and lamp with respect to said dead center axis to vary the oscillation and characteristics of the strip and load and thereby accommodate for various operating conditions.

3. An oscillating device as defined in claim 2, said means comprising an adjustable tiltable support for said lamp and said strip, whereby the extreme return swing position of the strip may be adjusted.

4. An oscillating device as defined in claim 2, in combination with means for selectively varying the amplitude of oscillation of said strip.

5. An oscillating device of the kind described, comprising a bracket, an electric lamp mounted on said bracket, a resilient deflectable strip having its lower end secured to a point of pivotal support on said bracket and extending upward therefrom in adjacent relation to said lamp, said strip including as a part thereof a bi-metallic element so shaped and positioned that the heat of the lamp is efieetive to distort it and by such distortion to initiate a swinging movement of the strip away from the lamp, a load carried by the free end of the strip and having its center of gravity so located that as the strip moves under the influence of said distortion the center of gravity is carried past the dead center axis which extends vertically through said point of support, thereby amplifying the swinging movement away from the lamp, a resilient member positioned on the side of said strip opposite to said lamp and having its lower end secured to said bracket, and adjustable abutment means on said member and engageable with said strip at the end of its outward swing.

6. An oscillating device as defined in claim 5, wherein said resilient member is arranged in spaced relation with respect to said strip, and said abutment means comprises a threaded element extending transversely through and in threaded engagement with said resilient member.

7. An oscillating device of the kind described, comprising a base, a bracket arranged above said base, a resilient bar interposed between and having spaced portions connected, respectively, to said base and said bracket to mount the latter for tilting movement with respect to said base, means for adjusting said bracket into various tilted positions, an electric lamp mounted on said bracket, a resilient deflectable strip having its lower end secured to a point of pivotal support on said bracket and extending upward therefrom in adjacent relation to said lamp, said strip including as a part thereof a bi-metallic element so shaped and positioned that the heat of the lamp is efiective to distort it and by such distortion to initiate a swinging movement of the strip away from the lamp, a load carried by the free end of the strip and having its center of gravity so located that as the strip moves under the influence of said distortion the center of gravity is carried past the .ead center axis which extends vertically through said point of support, thereby amplifying the swinging movement away from the lamp, the tiltable bracket mounting serving to position the load center of gravity a selected distance from said dead center axis when the load is in its extreme return swing position.

8. An oscillating device as defined in claim 7, in combination with a resilient member positioned on the side of said strip opposite to said lamp and having its lower end secured to said bracket, and adjustable abutment means on said member and engageable with said strip at the end of its outward swing.

9. An oscillating device as defined in claim 8, in combination with an opaque heat-conductive shield positioned between said lamp and said bimetallic element so that the latter establishes contact with and is heated by said shield on each return swing, said shield serving as a barrier to the transmission of radiant heat from the lamp to the space within which the movements of the bi-metallic element take place.

10. An oscillating device as defined in claim 9, said lamp including a substantially globular filament enclosure, said shield comprising a strip of metal conformably engageable with said enclosure and pivoted to said bracket for swinging movement into and out of said engaging relation, to vary the barrier effect and also permit replacement of the lamp.

11. An oscillating device of the kind described, comprising a source of heat, a resilient deflectable strip secured at one end to a point of pivotal support and extending in adjacent relation to said source, said strip including as a part thereof a main lei-metallic element so shaped and positioned that the heat of said source is effective to distort it and by such distortion to initiate a swinging movement of the strip away from said source, a load carried by the strip and having its center of gravity so located that as the strip moves under the influence of said distortion the center of gravity is carried past the dead center axis which extends vertically through said point of support, and a second bi-metailic element forming part of said strip and arranged with its heat responsive surfaces reversed relative to the main bi-metallic element.

12. An oscillating device as defined in claim 11, the location of said second bi-metallic element on said strip being between the main bi-metallic element and the point of pivotal support.

13. An oscillating device of the kind described, comprising an electric lamp having a gloubular filament enclosure, a resilient deflectable strip secured at its lower end to a point of pivotal support alongside said lamp, said strip extending upwardly and including as a part thereof a main bi-metallic element so shaped and positioned that it lies in close proximity to said globular enclosure and is distorted by the heat of the latter to initiate a swinging movement of the strip away from the lamp, a load carried by the swinging part of the strip and adapted to carry the strip past the dead center axis extending vertically upward from said point of support, and a second bi-metallic element forming the lower part of said strip and arranged with its heat responsive surfaces reversed relative to the main bi-metallic element.

References Cited in the file of. this patent UNITED STATES PATENTS Number Name Date 1,292,105 Shoenberg Jan. 21, 1919 1,804,709 Shoenberg May 12, 1931 2,561,217 Muir July 1'7, 1951 

